Shoot off tires:
 Aiming at tires and shooting where the bolts are, in the middle.
 This works best with the Tommy gun.

 Killing people in black suits:
 Walk behind them and shoot them. This works best with the sawed off shotgun.

 Fast reload:
 Press the reload key, then roll left or right.

 Free repair to damaged car in freeride mode:
 If you have a flat tire or any other damage to your car, just drive out to the 
 countryside (so that a loading screen appears). After the load, your car will be 
 fixed. 

 Lose cops quickly:
 Get to a rail station, elevated rail station, or trolley. Get in and wait until your 
 wanted level goes down.

 Ordinary Routine: Easier mission: 
 You can save some effort by shooting the tires on the getaway car before you try 
 to enter the hotel. It is much easier than trying to shoot them while driving at the 
 same time.

Get drunk
 In mission "Happy Birthday" when you are on steamboat (when you need to 
 assinate the concilour) go to the second floor and into the bar. 
 You will see a glass of wine on the to left of bar. Go there and push 
 "action button". Push as many times as you can (three times) and you will 
 get drunk. 
 
 
 Easy money:
 Bet a negative number at the casino to gain money every time you lose.
 
 Kill the men in the all black suits with the black hat (gangsters)
 to earn $500 each.
 
 Go into the country and speed in a fast car.

 Blow up cars for $100 each.

 Drive taxis to earn money